Effect of prenatal phthalate exposure on the association of maternal hormone levels during early pregnancy and reproductive markers in infants at the age of 3 months

Abstract

Phthalates belong to the endocrine-disrupting chemicals, altering the hormonal balance in humans during pregnancy with further effects on the reproductive system. This study aimed to investigate the associations between maternal hormone levels during early pregnancy (≤15th week of pregnancy) and reproductive markers in infant boys (n = 37; 61.67 %; average age 3.51 ± 0.73 months) and girls (n = 23; 38.33 %; average age 3.30 ± 0.33 months) concerning prenatal exposure to phthalates. We used high-performance liquid chromatography, tandem mass spectrometry (HPLC-MS/MS), and electro-chemiluminescence immunoassay to quantify urinary concentrations of phthalates and serum concentrations of hormones, respectively. In Mother-Infant Study Cohort (PRENATAL), we observed positive and negative correlations between infants' reproductive markers and phthalate metabolites (p ≤ 0.05). Next, we noticed associations between the penile length and maternal testosterone (β = 0.464) and estradiol levels (β = -0.365) with increasing significance after adjustment to maternal mono-n-butyl phthalate (MnBP) and monobenzyl phthalate (MBzP) (p ≤ 0.05). We observed a positive association (β = 0.337) between penile width and maternal testosterone with increasing significance after adjustment to maternal mono-iso-butyl phthalate (MiBP) (p ≤ 0.05). In a group of girls, we reported a negative association between ACD/AFD ratio and maternal follicle-stimulating hormone (FSH) and estradiol levels with increasing significance after adjustment to maternal monoethyl phthalate (MEP), MnBP, and mono(hydroxy-iso-butyl) phthalate (OH-MiBP). Our results highlight that prenatal phthalate exposure may modulate the effects of maternal hormone levels during early pregnancy on infants' reproductive markers.

Keywords: Hormones; Infants; Phthalate exposure; Reproductive markers.